Condensed Consolidated Statements Of Cash Flows (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013
Statement of Cash Flows [Abstract]
Net Cash Provided by Operating Activities of Continuing Operations	$ 165,711	$ 134,698
Cash Flows from Investing Activities of Continuing Operations:
Purchases of property and equipment	311,094	146,483
Proceeds from disposition of property and equipment	187,907	205,735
Investments in and advances to 50% or less owned companies	58,343	91,492
Return of investments and advances from 50% or less owned companies	31,549	10,642
Principal payments on third party leases and notes receivable, net	8,173	(2,604)
Net (increase) decrease in restricted cash	1,481	(7,392)
Net (increase) decrease in construction reserve funds and title XI reserve funds	59,539	33,392
Business acquisitions, net of cash acquired	35,000	10,540
Net cash used in investing activities of continuing operations	(254,174)	(55,534)
Cash Flows from Financing Activities of Continuing Operations:
Repayments of Debt and Capital Lease Obligations	18,969	13,129
Net borrowings (repayments) on inventory financing arrangements	(3,116)	4,183
Proceeds from issuance of long term debt, net of offering costs	11,464	10
Common stock acquired for treasury	127,151	0
Cash Received (Paid) For Share Settlements from Spinoff Transactions	0	(357)
Proceeds and tax benefits from share award plans	7,403	17,195
Issuance of noncontrolling interests	145,350	40
Purchase of subsidiary shares from noncontrolling interests	2,090	0
Cash received from (dividends paid to) noncontrolling interests, net	(1,056)	(3,822)
Net cash provided by (used in) financing activities of continuing operations	11,835	4,120
Effect of Exchange Rate Changes on Cash and Cash Equivalents	(1,175)	(643)
Net Increase (Decrease) in Cash and Cash Equivalents from Continuing Operations	(77,803)	82,641
Cash Flows from Discontinued Operations:
Operating Activities	0	24,298
Investing Activities	0	(8,502)
Financing Activities	0	(14,017)
Effects of Exchange Rate Changes on Cash and Cash Equivalents	0	143
Net Increase in Cash and Cash Equivalents from Discontinued Operations	0	1,922
Net Increase (Decrease) in Cash and Cash Equivalents	(77,803)	84,563
Cash and Cash Equivalents, Beginning of Period	527,435	248,204
Cash and Cash Equivalents, End of Period	$ 449,632	$ 332,767